Method of making toroidal seals



June 20, 1967 M. M. DELGODO 3,325,892

METHOD 0F MAKING TOROIDAL SEAL Original Filed Feb. 13, 1963 m IN m m 1. m m M ATTORNEYS.

United States Patent 3,325,892 METHOD OF MAKING TOROIDAL SEALS Manuel M. Delgado, 14525 Florita, La Mirada, Calif. 90638 Original application Feb. 13, 1963, Ser. No. 258,262, now Patent No. 3,188,100, dated June 8, 1965. Divided and this application Apr. 20, 1964, Ser. No. 365,552

5 Claims. (Cl. 29-529) This application is a division of Ser. No. 258,262 filed Feb. 13, 1963, now Patent No. 3,188,100, issued June 8, 1965.

This invention relates to the art of producing gas-tight metal seals which may be used at extremely high temperatures, and more particularly to an effective metal seal and to a method of manufacturing the seal.

Although the present invention may have a much larger scope of application and should not be limited to those uses specifically disclosed herein for that reason, the seal of the present invention has been found to be especially useful between annular metal flanges by which it is axially compressed. Metal seal material is used which performs its function effectively over a temperature range much larger than that of conventional organic sealants.

In the past, it has been the practice to use a harder plated metal body ribbed on both sides for a high temperature gas-tight seal. The plated metal is softer, but the material used therefor must be selected, at least in part, for its desirable electroplating property. The same is true of the harder metal body. Unfortunately, the functions of both metals in forming a gas-tight seal is completely unaffected by the electroplating property of each. It is in fact the mallea'bility of the soft metal that is the property of principal concern when it functions as a seal. In particular, hopefully the plated metal at the tips of the sea-l ribs is mechanically driven or compressed into extremely small grooves or scratches or tool marks in the contacting surfaces of a pair of annular flanges between which the metal seal body is compressed.

Due to the fact that it has not been possible to use extremely malleable plating metals because of their poor electroplating properties, plated metal seals have performed poorly. They have also suffered in their performance because it is not possible to electroplate a small, very sharp edge. Note will be taken that a small, sharp malleable metal edge may be deformed and driven or compressed into the small annular flange grooves much farther and with a substantially improved sealing elfect over that which may be produced with a large, dull malleable metal edge.

it is known in the art that a metal plated metal O-ring may be employed for a high-temperature gas-tight seal. However, it is not possible with such a seal to use a ribbed metal body because of a figure-eight deflection that the O-ring takes under a compression load.

The present invention overcomes the above-described and other disadvantages of the prior art by providing a seal including a relatively hard metal body clad with a relatively soft metal. 7

The word clad as used herein is a technical Word of art. A hard metal sheet is conventionally clad with a sheet of soft metal by preparing the surfaces of each of the sheets meticulously, sothat the same are absolutely smooth to within extremely small tolerances, carefully cleaning thesurfaces of the sheets, and pressing the two sheets together with an extremely high force, i.e. at pressures of millions of pounds per square inch to cause the sheets to adhere to one another by a molecular bond therebetween.

As stated previously, the cladding process described in the immediately preceding paragraph is conventional. Hence, no claim is, of course, made to that process or the "ice product thereof, i.e. clad metal sheet per se. However, it is an outstanding feature of the present invention that a hard metal sheet clad with a softer metal is employed as a seal in accordance with the present invention, because in this case, the material of the cladding sheet may be selected for its malleable property rather than for its electroplating property. This makes it an extremely valuable metal sea-ling material. Note will be taken that such was not possible in the case of prior art electroplated malleable materials.

In accordance with the present invention, the metal sheet thereof may include a toroidal shaped hard metal body having an annular slot through the internal surface thereof to provide a sealing ring of a C-shaped cross section. As stated previously, metal seals are in general clamped between annular flanges. Hence, the hard metal ring may be clad, on its external surface with a soft metal. The hard metal is preferably made of a material having a high resilience. Due to the fact that the soft metal is clad rather than electroplated in accordance with the prior art, it is in fact possible to select a hard metal of properties more suitable for a metal seal than was heretofore possible in accordance with prior art practices, because prior art practice required the use of a hard resilient metal suitable for electroplating.

In accordance with another outstanding feature of the present invention, the clad metal thereof may be located in a rib on the harder metal. It also may be provided with an extremely small width and may be machined to have an extremely sharp edge. This construction likewise is substantially improved over the rather large dull edge of prior art electroplated ribs in that the small, sharp, clad malleable metal of the present invention may be driven or compressed into the small grooves of the annular compressing flanges employed in high-temperature gas-tight seals.

.It is also a feature of the present invention that a ring of a C-shaped cross section be employed in lieu of the conventional metal O-ring of the prior art in that the C- shaped section of the ring of the present invention does not take a figure-eight deflection that the O-ring of the prior art does. Thus, the compression load may be provided directly on the small sharp edge of the malleable clad metal of the present invention.

It is also an outstanding feature of the present invention that a method is provided to fabricate a clad metal seal having a clad sealing malleable metal rib thereon of an extremely small width and an extremely sharp edge. This construction is produced in accordance with the method of the present invention including the step of removing spaced portions of a softer metal clad onto a harder metal to leave a rib of the softer metal on the harder metal between the said portions of the softer metal. It is also an outstanding feature of the present invention that this step of the method thereof may be performed in a manner such that the rib is left with a relatively sharp edge. The softer metal may be removed by machining. This is not possible with electroplated malleable metal because the same flakes off of the harder metal onto which the same is plated. It was, in fact, an outstanding discovery of the present invention that clad metal might be so machined.

The above described and outer advantages of the present invention will be better understood from the following description when considered in connection with the accompanying drawings.

In the drawings which are to be regarded as merely illustrative FIG. 1 is a top plan view of a ring seal made in accordance with the present invention;

FIG. 2 is a sectional view of the ring taken on the line 22 shown in FIG. 1; and

FIG. 3 is a broken away side elevational view of the portion of the ring shown in FIG. 2.

In the drawing in FIG. 1, a ring is is shown which may be constructed in accordance with the present inven tion. The detail of the structure of ring 10 is better illustrated in FIG. 2. It will be noted that a hard metal tube 11 is provided which is clad at 12, 13 and 14 with a softer metal. Opposite sides of ring 10 at 15 and 16 are machined fiat and the softer metal on the exterior of tube 11 at 15 and 16 is removed except for ribs at 17 and 18 respectively, which are provided with sharp edges at 19 and 21) respectively. Tube 11 is provided with an annular slot extending through the internal surface thereof around the complete interior of ring 10.

Ring 10 is made as follows. The metal of tube 11 is made in sheet stock and this sheet stock is clad with the sheet stock out of which soft metal at 12, 13 and 14 is made. The same is true of the soft metal at ribs 17 and 18. The hard metal of tube 11 may be stainless steel. This metal may have a relatively high resilience. The metal at 12, 13, 14, 17 and 18 may be copper.

The copper clad stainless steel sheet is then formed into a copper clad tube 11 with the copper on the external surface of the stain-less steel. The seam ofthe tube may be at the inner portion of the ring 10 and need not be welded together in that the seam is eventually slotted at 21 anyway. The slot 21 may be machined in tube 11. The ends of the tubing 11 may be butt welded together and the weld ground flush with the external surface of the ring 10. If desired, the slot 21 may be milled after the ring 10 has been formed by butt welding and grinding the weld. Opposite sides of ring 11 are then machined fiat as at 15 and 16 leaving copper ribs 17 and 18 having relatively sharp edges at 19 and respective-1y.

From the foregoing, it will be appreciated that by cladding tube 11 instead of electroplating the same, it is possible to select a material for tube 11 for maximum strength, chemical resistance and/or temperature resistance suitable to the specific application. Still further, the soft metal at 12, 13, 14, 17 and 18 may be chosen for maximum malleability, ductility, chemical resistance and/ or temperature resistance suitable to the specific application. Note will be taken that the present invention therefore is substantially improved over that of the prior art in that the prior art hard and soft metals of the metal seals thereof have, in the past, had to be selected on the basis of their suitable electroplating property. The seal of the present invention also is substantially improved over that of the prior art. That is, edges 19 and 20' of ribs 17 and 18 can be made extremely sharp. This is true notwithstanding the fact that, as stated previously, it was impossible to produce such sharp edges with prior art electroplated soft metals in that such metals flake off of a hard base metal and cannot therefore be machined. This also explains the outstanding feature of the present invention in providing ribs 17 and 18 by machining the soft metal cladded onto tube 11.

The C-shaped cross section of ring 10, as shown in FIG. 2, also makes it possible to locate the compressive force of the annual compressive flanges of the prior art on the very sharp edges 19 and 20 of ribs 17 and 18 respectively and at no other point as would normally be required with metal O-ring seals of the prior art.

The phrase toroid-like as used herein and in the claims to follow is hereby defined to include any ring-shaped body which has any cross section, circular or otherwise.

Note will be taken that ring 10 has an axis. That is, it has an. axis which is perpendicular to the drawing in FIG. 1 at the center of the concentric circles therein. It is this axis to which the word axis herein and in the claims to follow refers.

Although only one specific embodiment of the present invention has been described and illustrated herein, many changes and modifications will of course suggest themselves to those skilled in the art. This single embodiment has been selected for this disclosure for the purpose of illustration only. The present invention should therefore not be limited to the embodiment so selected, the true scope of the invention being defined only in the appended claims.

What is claimed is:

1. The method of making a seal comprising the steps of: cladding a sheet of stainless spring steel with a layer of copper softer and less resilient than said steel; forming the clad sheet into a toroid with the copper layer at the external surface thereof; butt welding the ends of said toroid together to form a ring; grinding the weld flush with the external surface of the toroid; machining a slot through said toroid around the inner circumference thereof; and machining away two spaced portions of said copper layer on each of the opposite sides of said ring in a manner leaving a rib on each side having a relatively sharp edge, the edges of said ribs being oppositely directed.

2. The method of making a seal comprising the steps of: forming a toroid out of a spring metal tube having its external surface clad with a malleable metal softer and less resilient than said spring metal; machining an annular slot through the internal surface of said toroid; and removing said malleable metal from two portions of said spring metal on each of the opposite sides of said toroid spaced radially from the axis thereof to provide a rib on each such opposite surface.

3. The method of making a seal, said method comprising the step of: forming a hollow, toroid-like body out of a spring metal clad on its external surface with a malleable metal softer and less resilient than said spring metal, said malleable metal being positioned on the external surface of said body at least in solid rings approximately tangent to said body in planes perpendicular to the axis of said body.

4. The method of making a seal, said method comprising the steps of 2 cladding a fiat sheet of spring metal with a malleable metal softer and less resilient than said spring metal; and forming said clad body into a hollow, toroidallike ring with said malleable metal being positioned on the external surface of said hollow ring at least in solid rings tangent to said hollow ring approximately in planes perpendicular to the common axis of said rings.

5. The method of making a seal comprising the steps of: forming a toroid out of a spring metal tube having its externalsurface clad with a malleable metal softer and less resilient than said spring metal; machining an annular slot through the internal surface of said toroid; and removing said malleable metal from two portions of said spring metal on each of the opposite sides of said toroid spaced radially from the axis thereof to provide a rib on each such opposite surface, said removing step being performed in a manner such that said ribs are left with oppositely directed relatively sharp edges.

References Cited UNITED STATES PATENTS 192,167 6/1877 Huguenin 29481 XR 816,478 3/1906 Kirshning. 1,834,581 12/1931 Ferrell et a1. 2,289,620 7/ 1942 Bernstein. 2,476,151 7/ 1949 Le Jeune 29-529 JOHN F. CAMPBELL, Primary Examiner.

P. M. COHEN, Assistant Examiner, 

1. THE METHOD OF MAKING A SEAL COMPRISING THE STEPS OF: CLADDING A SHEET OF STAINLESS SPRING STEEL WITH A LAYER OF COPPER SOFTER AND LESS RESILIENT THAN SAID STEEL; FORMING THE CLAD SHEET INTO A TOROID WITH THE COPPER LAYER AT THE EXTERNAL SURFACE THEREOF; BUTT WELDING THE ENDS OF SAID TOROID TOGETHER TO FORM A RING; GRINDING THE WELD FLUSH WITH THE EXTERNAL SURFACE OF THE TOROID; MACHINING A SLOT THROUGH SAID TOROID AROUND THE INNER CIRCUMFERENCE THEREOF; AND MACHINING AWAY TWO SPACED PORTIONS OF SAID COPPER LAYER ON EACH OF THE OPPOSITE SIDES OF SAID RING IN A MANNER LEAVING A RIB ON EACH SIDE HAVING A RELATIVELY SHARP EDGE, THE EDGES OF SAID RIBS BEING OPPOSITELY DIRECTED. 